The invention relates to an apparatus for needling a non-woven with at least one support for a needleboard held in a frame and with two parallel eccentric drives made of two parallel eccentric shafts each for the needleboard drive in the needling direction on the one hand and in the direction of passage of the non-woven on the other hand.
In order to increase the non-woven advance it is known (DE 196 15 697 A1) to provide an additional needleboard drive which reciprocates in the direction of passage of the non-woven, so that the non-woven advance is increased by the movement component of the needleboard in the direction of passage of the non-woven. Said additional drive for the needleboard is formed like the main drive acting in the direction of the needle penetration by an eccentric drive which is articulated by way of connecting rods on the needle beam. The arrangement of two parallel eccentric shafts leads to a parallel guidance of the needle beam because the connecting rods form the guide rods of a parallelogram of links. In order to set the stroke the connecting rods can be held on the eccentric shafts by way of adjusting eccentrics, by means of which the eccentricity of the eccentric shafts is changed.
If a parallel guidance of the needle beam is omitted (EP 0 892 102 A2), the connecting rods of the two eccentric shafts can be coupled with one another by way of a coupling bridge which acts on the needle beam by way of a guide rod. In such an arrangement of the eccentric drive for the needleboard drive in the direction of passage of the non-woven, the needleboard advance in the direction of passage of the non-woven can be set by a respective choice of the mutual angular position of the two eccentric shafts of the eccentric drive. The price to be paid for this simple possibility for setting the needleboard drive in the direction of passage of the non-woven is the disadvantage that the needleboard which is articulated in the needle penetration direction on the connecting rods of the eccentric drive for the needleboard drive performs a reciprocating swiveling movement with the disadvantage that the thus produced swiveling movements of the needles cause an enlargement of the penetration holes in the non-woven during the needle penetration. Apart from that, there are considerable constructional efforts required for needleboard supports which are articulated by way of connecting rods on eccentric drives.
The invention is thus based on the object of providing an apparatus for needling a non-woven of the kind mentioned above in the aforementioned manner in such a way that on the one hand, a simple construction for needleboard operation is enabled in the direction of needle penetration as well as in the direction of passage of the non-woven, and that on the other hand preconditions are created for an advantageous setting of the needleboard advance in the direction of passage of the non-woven without requiring any pivoting of the needleboard.
This object is achieved by the invention in such a way that an intermediate support is provided between the needleboard support and the frame and that the intermediate support is guided with respect to the frame and the needleboard support with respect to the intermediate support by way of the two eccentric drives which are disposed on the one hand between the frame and the intermediate support and on the other hand between the intermediate support and the needleboard support.
Since as a result of these measures the intermediate support is held directly on the eccentrics of the eccentric shafts of the one eccentric drive as held in the frame, and on whose eccentrics the needleboard support rests directly, a simplification of construction is obtained in comparison with eccentric drives which act by way of connecting rods on the needleboard support, leading to the effect that both eccentric drives influence the movement of the needleboard support both in the direction of needle penetration as well as in the direction of passage of the non-woven. Under the assumption of a coinciding eccentricity and a dead center position of the two eccentric drives which is mutually offset by 180xc2x0 in the direction of the viewed direction of stroke, their strokes cancel one another out for example, whereas in the case of a corresponding angular position of the eccentric drives a total stroke is obtained which corresponds to the sum total of the two individual strokes. If the two eccentric drives are driven in opposite direction, opposite strokes in the direction of advance which mutually cancel each other out are obtained in a corresponding dead center position in the direction of needle penetration, so that the needleboard is driven exclusively so as to reciprocate in the direction of needle penetration. As a result of adapting the mutual angular positions, the eccentricities and the direction of rotation of the eccentric drives it is thus possible to create drive conditions for the needleboard which advantageously meet the respective requirements both with respect to the direction of needle penetration as well as the advance in the direction of passage of the non-woven.
An additional factor is that for adapting the needleboard drive to different advances in the direction of passage of the non-woven it is merely necessary to set the mutual angular position of the eccentric drives. The corresponding angular position of the two eccentric shafts of each eccentric drive secures a movement of the needleboard parallel to itself along a closed orbit, so that swiveling movements of the needleboard can be excluded, although the needleboard can also be superimposed with a swiveling movement in special cases.